Avoid NREs in MVC sample
- see e.g. results of `GET ~/Home/Post`
- use parentheses to avoid `?` confusing Razor

nit: remove unused Home/Test.cshtml view
Extend MVC Sample functional test to include all Home views
Touch up tag helper sample
- provide list of users on Index page
 - currently uses only the `<a/>` helper but left `<label/>` and `<input/>` comments
- get date picker working on Create and Edit pages
 - add `[DataType]` annotation
 - use format browsers recognize

nits:
- move "Create New" link to the bottom of `~/Home/Index`
- correct code comment about assigning to a `ViewBag` property
React to aspnet/Razor#210 changes.

- Added the ErrorSink pass through values for our overridden classes.
React to GetDefaultServices/TryAdd changes
Adding support for property level binding using IBinderMetadata and enabling FromXXX attributes to be decorated on properties.
Updating Associated Metadata Provider to follow the existing pattern.
Adding support for ModelMetadataAttribute in core.